The present invention relates to carburetors for small internal combustion engines and more particularly, to fuel primers for float type carburetors providing fuel into the combustion chamber prior to starting of the internal combustion engine.
Small internal combustion engines, especially marine outboard motors with float type carburetors and the like, generally need to be primed before starting of the engine occurs. Priming is the pre-drawing of fuel into the combustion chamber of the cylinders prior to the starting of the internal combustion engine. Generally, after an internal combustion engine sits for a long period of time, e.g. two weeks or greater, fuel in the combustion chamber evaporates. This evaporation of fuel necessitates priming of the combustion chamber so that fuel is present to start the engine. A dry combustion chamber generally causes the operator to pull on the starting cord several more times than he would if the combustion chamber contained a supply of fuel.
Generally, the starting procedure for an internal combustion engine having a float type carburetor is as follows. The choke is set in an on position and the throttle is set in its start position. The carburetor bowl is filled with fuel and then the engine cord is pulled several times. Generally, during the pulling of the cord, the engine fires and quits due to excessive fuel entering the combustion chamber. The choke is then put in the off position. Several pulls of the rope are usually required after choke off to start and run. Sometimes the engine will quite again and the above procedure must be repeated until engine eventually starts and continuously runs. Normally, several pulls (approximately 8-10) of the starter cord are needed to accomplish starting of the internal combustion engine.
In some applications of outboard motor carburetor designs, attempts were made to provide a spring loaded breakaway butterfly choke for enabling proper air/fuel ratio to be passed into the combustion chamber. These designs, however, would not accomplish a start and run condition without stopping, therefore, defeating the purpose of the device. Thus, the art has the disadvantage that the engine can not be started and continue to run without pulling on the engine cord several times to prime the engine. Also, the art does not provide an operator with sufficient time to move the butterfly choke from a closed, to a run position while the engine is warming up. Thus, the engine is unable to run without stopping from a start up to a continuous run condition.
Accordingly, it is an object of the present invention to overcome the disadvantages of the above art. The present invention provides the art with a fuel primer for float type carburetors. The present invention enables an internal combustion engine, having a float type carburetor to start and continue to run without stopping during an intended warm-up period. The present invention enables the operator to position the butterfly choke from a closed, to a run position during engine warm-up without stalling. Also, the present invention enables fuel to be drawn into the combustion chamber of the engine cylinders utilizing existing inlets and outlets of conventional float type carburetors.
The float type carburetor fuel primer of the present invention is associated with a fuel bowl of a float type carburetor. The fuel bowl is generally coupled with a fuel inlet and has an outlet to ambient air. Also, the fuel bowl is associated with the carburetor venturi through a nozzle which discharges fuel from the fuel bowl into the combustion path. The fuel inlet is associated with a fuel source for enabling fuel to enter into the fuel bowl. The fuel primer includes a mechanism coupled with the atmospheric outlet vent for introducing a pressurized flow, via the atmospheric outlet vent, into the fuel bowl. The pressurized flow introduces fuel in the fuel bowl to pass, via the nozzle, into the combustion path which, in turn, enables the fuel to pass into the combustion chamber.
Generally, the mechanism for introducing pressurized flow into the fuel bowl includes a resilient mechanism coupled with the atmospheric outlet vent. The resilient mechanism pressurizes the primer upon compression. An activation mechanism is associated with the resilient mechanism. The activating mechanism compresses the resilient means upon activation, thus activating the primer.
From the following description and claims taken in conjunction with the accompanying drawings, other objects and advantages of the present invention will become apparent to one skilled in the art.